Subj : MESO: Nws Weather Prediction Center College Park Md To : wx-storm@lists.illinois.edu From : COD Weather Processor Date : Mon Jul 28 2025 04:52:59 AWUS01 KWNH 280452 FFGMPD MNZ000-IAZ000-SDZ000-280900- Mesoscale Precipitation Discussion 0815 NWS Weather Prediction Center College Park MD 1250 AM EDT Mon Jul 28 2025 Areas affected...Eastern SD...Southwest MN...Northwest IA Concerning...Heavy rainfall...Flash flooding possible Valid 280450Z - 280900Z SUMMARY...Some isolated areas of flash flooding will continue to be possible overnight in association with a strong MCS impacting portions of the Upper Midwest. DISCUSSION...The latest GOES-E IR satellite imagery shows a strong cold-topped MCS advancing southeastward across the Upper Midwest. The convection is interacting with a very moist and unstable southwest low-level jet of 20 to 30+ kts out ahead of it, with much of the stronger convection becoming aligned around the southwest flank of the MCS where the low-level flow is oriented more perpendicular to the convective mass. MLCAPE values across far southeast SD and through much of western and central IA are on the order of 4500 to 5500 J/kg. This extreme instability coupled with at least some additional nocturnal enhancement to the low-level jet over the next few hours should favor a relative persistence of stronger convection in a northwest to southeast fashion from portions of southeast SD through southwest MN and especially down across northwest IA at least over the next few hours. Some cell-training concerns will exist across this specific corridor while the remainder of the larger scale MCS off to the east continues to bow progressively down to the southeast in association with the cold pool. Rainfall rates with the remaining stronger storms around the southwest flank of the convective mass will still be capable of reaching 1 to 2 inches/hour, and with some localized cell-training concerns, some additional rainfall totals of 2 to 4 inches will be possible. This is consistent with the 00Z HREF guidance. These additional rains will maintain a threat for mainly isolated areas of flash flooding in the near-term before the heavy rainfall threat diminishes later tonight. Orrison ....Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!= DZ3fjg!7TsMtKHWIA2PYnGxUB-wr-SPQlOaxNyEVwsAQ1QUXge7ffEU07W88GjThtWrI8jAnqU8= Dm9A8YhVHpRtNAFZ1OYFSSw$ for graphic product... ATTN...WFO...ABR...DMX...FSD...MPX...OAX... ATTN...RFC...KRF...MSR...NWC... LAT...LON 45049679 44549535 43399351 42309335 41719415=20 41779516 42119581 43099649 44589756=20 =3D =3D =3D To unsubscribe from WX-STORM and you already have a login, go to https://lists.illinois.edu and use the "Unsubscribe" link. Otherwise email Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM. --- SBBSecho 3.28-Linux * Origin: capitolcityonline.net * Telnet/SSH:2022/HTTP (1:2320/105) .